Suppression of soot of a diesel engine fueled with biodiesel-diesel blends

The characteristics of spray, combustion, and soot emissions of the diesel engine fueled with biodiesel–diesel blends and diesel are numerically simulated using AVL‐FIRE software to illustrate the suppression effect of biodiesel on in‐cylinder soot. The model was validated by comparison with experimental cylinder pressure and smoke for the baseline engine at rated power. The results indicate the spray penetration distance of the blends is farther than that diesel. Compared with that of diesel, the evaporated fuel mass of 10 and 20% (vol) biodiesel blending with diesel (donated as B10 and B20) are almost the same. The Sauter mean diameter (SMD) of the blends is greater than that of diesel from 11° before top dead center (BTDC) to 7° BTDC, and then SMD of the blends is less than that of diesel. The equivalence ratio of the blends is lower that that diesel except at the end of injection, leading to the tendency of sooting. The ignition timing advances as the percent of biodiesel in the blend increases, helpful to reduce soot formation. The soot mass fraction for B20 decreases by 35.5% at exhaust valve opening, while it for B10 and 50% (vol) biodiesel blending with diesel (B50), decreases by 14.9 and 14.1%, respectively. The mean soot diameter and particle number of diesel give the bimodal distribution while those of the blends do trimodal distribution. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 282–288, 2015